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About this blog

I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.
I'm a world-famous podcaster and screencaster (albeit VERY thinly spread). :-)

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There was a time before blogging and what I'm about to talk about is something I used to explain quite often back in those days. Reminded by a current customer situation - and needing to explain it again - I thought it time to do it this way. (Here I'm presenting a simplified view, but one that covers the salient features that might help you.) The CICS / DB2 Connection code provides a number of... [More]

I don't know how many years it's been since DB2 Version 8 was shipped but I've FINALLY added support for some really useful statistics that became available with that release. As so often happens I was caused to open up my code because of some customer data that exposed a problem in it: The customer sent DB2 Version 8 SMF 101 Accounting Trace data that contained Unicode. In particular DB2... [More]

This may be stating the obvious - but I wonder to whom it actually is obvious... I've been doing quite a lot of work with batch job timings and CPU recently. (Everything I'm about to say is equally true of steps.) It's interesting to think about the effects of faster engines versus more engines (a question I haven't been asked recently) and whether a customer needs more capacity or just faster... [More]

When tuning DB2 batch it's important to know which SMF 101 Accounting Trace record corresponds to which job step. A few years ago I wrote code to do this. It works fine for all z/OS DB2 Batch except that originated by IMS. Here's how it works: Find all the Type 30 Step-End records for a given job name. Find the Type 101 Accounting Trace records for which the Correlation ID in the 101 record... [More]

Up until now I haven't talked much about DB2, except perhaps to
note it's a little different. But what is a DB2 Batch job anyway? It's
important to note a DB2 job ISN'T necessarily exclusively DB2 - although
some are. It's just a job that has some DB2 in it. The reason for writing a separate post, apart from breaking things
up a little, is because batch jobs with DB2 in them present... [More]